Mardia’s Coefficient of Multivariate Kurtosis as a Measure of Thermalization

The thermalization of strongly interacting, disordered quantum systems is not fully understood. Differentiating between pre-thermalized, metastable, and statistically thermalized states is challenging. We have developed a technique to use Mardia’s coefficient of multivariate kurtosis to quantify if an atomic gas has fully thermalized. We measure the in-situ density profile of thermal Bose gas for variable hold times after a perturbation has been applied using a repulsive optical potential. We find that Mardia’s coefficient is sensitive to small deviations from equilibrium.